Field of the Invention
The present invention relates to the determination of a temperature of a clutch. In particular, the invention relates to the determination of the temperature of a clutch for a hybrid drive.
Description of the Related Art
A clutch in a drive train, in particular on board a motor vehicle, is set up to transfer torque between a drive motor and a following component, in particular a transmission, by means of frictional grip or a cohesive frictional grip provided by the clutch. The temperature of the clutch depends to a significant degree on the amount of torque being transferred through it, and how much slip occurs between an input side and an output side of the clutch. Since both those sides are usually rotatable relative to and within a clutch housing, it is difficult to measure the clutch temperature directly. In order to be able nevertheless to provide a warning of excessive clutch temperature, attempts are frequently made to determine the clutch temperature on the basis of other measured variables.
DE 10 2005 061080 A1 discloses a method and a device for assessing a clutch state on the basis of external measurements.
In a hybrid drive, a first and a second drive motor are coupled to a shaft, which provides torque for the drive train. In different operating states the first, the second, or both drive motors can deliver torque to the shaft. Situations can arise in which a calculated determination of the clutch temperature does not keep up well with the actual conditions.